Percussive tool having improved handle fastening means



March 30, 1965 A. s'rowELL PERCUSSIVE TOOL HAVING IMPROVED HANDLE FASTENING MEANS Filed May 16, 1962 2 Sheets-Sheet l INVENTOR. AUSTIN L. STOWELL //wmw dma( ATTORNEYS March 30, 1965 A. l.. sTowELl.

PERCUSSIVE TOOL HAVING IMPROVED HANDLE FASTENING MEANS 2 Sheets-Sheet 2 Filed May 16, 1962 FIGS FIG. 7

. INVENTOR. AUSTIN I... STOWELL BYW,

ATTORNEYS United States Patent O 3,175,232 PERCUSSIVE T901. HAVING IMPRVED HANDLE FASTENlNG MEANS Austin L Stowell, New Britain, Conn., assigner to The Stanley Works, New Britain, Conn., a corporation of Connecticut Filed May 16, 1962, Ser. No. 195,237 7 Claims. (Cl. 7 8) The present invention relates to hand tools having a striking head and a non-integral handle secured in an aperture extending through the head, and more particularly to such hand tools for percussive applications having an irnproved connection between the striking element or head and the handle, and to the method of making same.

In hand tools for percussive use such as hammers, axes,

` hatches, sledges and the like, it is generally customary to provide the striking element or head with a handle-mounting aperture or eye which is usually outwardly tapered either throughout or a part of its length and into which one end of a handle is inserted and then locked in place by one or more wedges driven into the end of the handle so as to expand or enlarge the end of the handle into the outwardly tapered portion of the eye, thus retaining the handle therein. Such tools in normal use are subjected to a variety and combination of forces and strains tending to separate or loosen the connection between the head and the handle. In addition to the obvious percussive and vibratory forces occurring when the head is struck against another surface, there are the centrifugal and momentum forces occurring when the tool is swung or oscillated in an arcuate direction during a striking action, all of which tend to cause relative movement of the head, handle and wedges which result in loosening and deterioration of the connection and eventual separation. Also, such tools are frequently used for purposes other than striking such as for prying or pulling which, because of the relatively large leverages involved, can distort and strain the connection to the point of loosening and separation of the parts. A further complication arises where the parts of the tool which may include the handle and/ or `the wedges and/ or the head are made of non-metallic material such as wood which is subject to swelling and shrinkage in accordance with moisture changes. Over extended periods of use, particularly under drying conditions, there is a tendency for the non-metallic parts to lose moisture and thereby to shrink somewhat and loosen the otherwise tight lit in the eye of the striking element, thereby rendering them more susceptible to damage due to the percussive, centrifugal and leverage forces and strains referred to, particularly if the shrinkage permits the end of the handle to return to its approximate original size so that it can pull out of the eye. Similarly, excessive moisture conditions will tend to produce swelling due to moisture absorption,

l and excessive stresses may be produced by the swelling as well as an increase in the tendency for the handle to loosen when moisture is subsequently lost therefrom.

It is the aim of the present invention to provide a hand tool for percussive and prying or leverage use wherein the handle is firmly bonded to the striking element with direct handle-striking element surface contact substantially throughout in `the direction of percussive and prying or leverage forces, and wherein the end of the handle received in the striking element is protected from the atmosphere and contamination by liquids and solids.

A related aim is to provide a method for making such percussive tools conveniently and effectively so as to ensure a well-bonded and protected handle end having direct handle-striking element surface contact substantially throughout in the direction of percussive force.

Still another aim is to provide such a tool and method of making same wherein the improved connection is highlCC ly reliable, simple and relatively economical and wherein the parts thereof may be readily manufactured and aS- sembled.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangements of parts which will be exemplified in the construction hereafter set forth and the scope of the application which will be indicated in the appended claims.`

In the drawings:

FIG. l is a top view of a claw hammer embodying the improved handle connection of the present invention with the adhesive omitted for purposes of clarity of illustration;

FIG. 2 is a fragmentary longitudinal section of the harnmer along the line 2-2 of FIG. l;

FIG. 3 is a fragmentary transverse section of the hammer along the line 3-3 of FIG. 1;

FIG. 4 is a fragmentary side elevational view of a softface hammer embodying the present invention with portions thereof broken away to reveal internal construction;

FIG. 5 is a fragmentary transverse section of the softface hammer of FIG. 4;

FIG. 6 is a top view of a hatchet embodying the improved connection of the present invention with the adhesive omitted for purposes of clarity of illustration;

FIG. 7 is a fragmentary longitudinal section of the hatchet aiong the line '7-7 of FIG. 6; and

FIG. 8 is a fragmentary transverse section of the hatchet along the line 8 8 of FIG. 6.

It has now been found that the foregoing and related aims can be readily attained by a hand tool having one end of the handle seated in the eye of the striking element and forced into firm, direct surface engagement with the surface of the eye throughout in the direction of percussive forces by one or more wedges and having a slight spacing between its side portions and the surface of the eye in the direction transversely of percussive forces terminating inwardly of the bottom or entrance end of the eye in the striking element. The end of the handle is spaced inwardly of the exit end of the eye and impactresistant, synthetic resin adhesive covers the end of the handle and the wedge, lls the spacing between the sides of the handle and the eye and tlls any fissures or cavities in the handle. In this manner, a strong bond is produced between the handle and head as well as between the wedge and handle preventing separation and dimensional changes, and the end of the handle is protected from contamination and from the atmosphere so as to effectively eliminate moisture loss or absorption. In this construction, direct surface contact between handle and head is maintained through the depth of their opposed surfaces in the direction of percussive forces so as to insure firm engagement and full use of all physical properties of the handle material therebetween for optimum operating characteristics and long life.

Referring now in detail to the drawings, FIGS. 1-3 illustrate a claw hammer constructed in accordance with the present invention and generally comprised of a hammer head or striking element 2 and handle 4. The hammer head 2 has the customary poll and bell 6 and claws 8 at opposite ends thereof and a medial or socket portion 1t? having a downwardly extending shank 12. EX- tending through the socket portion 10 and its shank 12 approximately normal to the longitudinal axis of the claws 8 and poll and bell 6 and thereby the direction of percussive and pulling or leverage strains or forces is a generally rectangular handle-mounting aperture or eye 14 with an entrance end 16 and an exit end 1S. As can be seen in FIGS. 2 and 3, the eye 14 has walls which are substantially smooth and unbroken and the cross section of the eye may be uniform but preferably tapers slightly inwardly for a distance inwardly from the entrance end 16 so as to provide a wedging fit when the end of the handle is driven therein. The upper portion of the eye then gently diverges or tapers outwardly towards the exit end 18.

Driven into the entrance end 16 of the eye 14 is one end of the non-metallic handle 4, which handle end is of generally rectangular cross section and somewhat reduced in size with respect to the major portion thereof. The configuration and dimensions of the handle end 20 and eye 14 are such that the periphery of the handle end enters into close-iitting surface contact with the surface of the eye from the entrance end 16 to the outwardly tapering portion thereof. However, as initially assembled, some spacing exists between the periphery of the handle end 20 and the surface of the eye 14 extending inwardly from the exit end 18 thereof substantially to the point where the walls begin to taper outwardly. Only the transverse spacing is illustrated in FIG. 3 since the spacing in the direction of percussive force has been eliminated by the expansion of the end of the handle upon insertion of the wedge 22. As best seen in FIG. 2, the extreme end of the handle 4 terminates adjacent to but slightly inwardly of the exit end 18 of the eye so as to provide a small pocket thereat.

In this embodiment, a single wooden wedge 22 has been driven into the end 20 of the handle in the exit end 18 of the eye 14. The wedge 22 is dimensioned and configured to expand the material of the handle into rm, direct surface Contact with the surface of the eye 14 in the direction of percussive and leverage strains or forces substantially throughout the depth of the eye.

Filling the spaces between the sides of the handle end 20 and the eye 14 and extending across the extreme end of the handle (not shown in FIG. l for purposes of clarity of illustration) is a cured, impact-resistant, synthetic resin adhesive 24. Since the wedge 22 has forced the handle end 20 into firm direct contact with the surface of the eye in the direction of percussive and leverage strains or forces, the subsequently applied adhesive 24 only fills the side or transverse spaces and extends across the extreme end of the handle. This adhesive 24 provides a rm bond between the head 2 and handle 4 in the transverse direction, bonds the wedge 22 into place, lls any fissures or cavities in the non-metallic handle 4 to strengthen it, and seals the extreme end of the handle 4 (and wedge 22) to limit if not prevent moisture loss or absorption and contamination.

In FIGS. 4 and 5, there is illustrated a soft-face harnm'er embodying the present invention and generally comprised of the handle 26 and the metallic head or striking element 28 which has a pair of tubular tip-mounting sockets 29 in which are seated relatively soft striking tips 31. In this hammer, the eye 30 in the head 28 is generally circular in cross section with the sidewall thereof flared or tapered outwardly to the exit end 34 from a point spaced inwardly of the entrance end 32 and inwardly from the same point to the entrance end. The end 36 of the handle 26 is similarly driven into the eye 30 and wedgingly engages the periphery of the eye 30 for a distance inwardly from the entrance end 32.

In this embodiment, the sides of the generally cylindrical handle end 36 have been cut as indicated by the numeral 38 to provide a bevel increasing the spacing between the sides of the handle end 36 and the surface of the eye 30 adjacent the exit end 34 thereof. The

` wooden wedge 40 forces the material of the handle end 36 into firm, direct surface engagement with the surface of the `eye throughout its depth in the direction of percus- 'sive force. The subsequently applied impact-resistant,

`'synthetic resin adhesive 42 fills the notched-out areas SSandany otherspacing or fissures and extends across theextreme end of the handle 26 to firmly bond the 4 handle and wedge and to seal the end of the handle from the atmosphere and contamination.

In FIGS. 6-8, there is illustrated a hatchet employing the improved connection of the present invention and which is generally comprised of the handle 44 and the head or striking element 46 with its blunt striking face 48 and blade 59. The eye 52 in this striking element is of generally tear-shaped cross section and similarly has sidewalls which diverge or taper outwardly toward the exit end 54 of the eye from a point spaced inwardly of the entrance end 58 so as to provide spaces between the side surfaces of the eye and the sides of the handle end portion 56. Additionally, to increase the purely frictional engagement between the handle and head adjacent the entrance end 58 of the eye, the side portions of the eye transversely of the direction of percussive force taper inwardly from the entrance end 58 to the point where the walls of the eye commence to diverge towards the exit end 54 of the eye, as best seen in FIG. 8.

The material of the handle end portion 56 is expanded by a metal wedge 60 into rm, direct surface engage-l ment with the surface of the eye in the direction of percussive and leverage strains or forces and the impactresistant, synthetic plastic adhesive 62 (not shown in FIG. 6 for purposes of clarity of illustration) fills the spacing between the handle end portion and the surface of the eye and extends across the extreme end of the handle to firmly bond the handle 44 and wedge 60 in place and to seal the handle end from the atmosphere and contamination.

In each of the several embodiments, it can be seen that the handle and eye are in firm direct surface engagement about their periphery adjacent the entrance end of the eye and that the wedge forces the material of the handle into rm, direct surface engagement with the surface of the eye throughout the depth thereof in the direction of percussive and leverage strains or forces. The impact-resistant, synthetic plastic adhesive then fills the spacing between the sides of the handle and eye transversely of the direction of percussive and leverage strains or forces adjacent the exit end of the eye and extends across the end of the handle so as to firmly bond the handle and the wedge in place and to seal the handle (and the wedge when it is fabricated of a material subject to moisture change) from the atmosphere and contamination.

Since the handle and striking element are in firm, direct surface contact in the direction of percussive and leverrage strains or forces, the percussive and leverage strains or forces are transmitted directly therebetween for optimum operating characteristics. Due to the large area of direct surface contact between the handle and striking element, there is substantially complete elimination of any tendency for relative vibration which would reduce the hammer life significantly.

The present invention is applicable to various types of handles which may be utilized with wedges and particularly those which are subject to moisture change. Accordingly, handles of various non-metallic materials may be employed including wood, wood laminates such as those formed by bonding wood veneers impregnated with phenol-aldehyde and melamine-aldehyde resins, and ber reinforced plastics such as glass-fiber reinforced polyesters.

The synthetic resin adhesive employed must have high impact resistance but a resilient or rubbery material is considerably less effective than one which is relatively rigid. The adhesive should also have the properties of good or excellent adherence to metal and non-metallic heads and handles, low shrinkage, heat resistance, cold resistance, moisture resistance, and preferably ambient or low-temperature curing.

Among the adhesives which may be employed are the following: liquid aromatic epoxy resins Such as bis- `methon 4,4diisocyanate reacted with castor oil.

The adhesives may be modified with various fillers to alter the hardness and flexibility and may also include pigments or dyes to provide various colors. Various curing agents may be employed such as the well-known amine, amide and boron trifluoride catalysts for the epoxy reslns.

In the process of making the hand tools of the present invention, the eye of the hammer head should be thoroughly clean and free from grease or rust, and the handles should be clean and dry. The end .of the handle is inserted into the entrance end of the eye and driven into place so that the periphery of the handle and eye will be in firm direct surface contact for a distance inwardly from the entrance end of the eye and the material of the handle will tend to form a slight shoulder abutment against the lower edge of the head adjacent the eye. The handle Aand head are so dimensioned that the extreme end of the handle terminates slightly inwardly of the exit end of the eye, a distance of about lA to 1A inch being satisfactory.

One or more wedges, which may be of wood, metal or other suitable material, are then driven into the end of the handle in the exit end of the eye so as to expand the material of the handle into firm direct surface engagement with the end in the direction of percussive and leverage strain or forces throughout the depth of the eye.

The handle and eye are so dimensioned and configured, either by fabrication, dimension or by removal of a portion of the material as in FIG. 5, so as to provide spacing between the handle and the surface of the eye in the direction transversely of percussive forces for a distance inwardly from the exit end of the eye even after the wedge has been driven into place. Generally, a spacing at the extreme end of the handle of about 1A@ to 1,4 inch is satisfactory.

The tools are then assembled in vertical position with the exit end vof the eye uppermost, preferably after having the striking elements or heads preheated to a temperature of about 12S-200 F. to facilitate flow of the synthetic resin adhesive and subsequent curing thereof. The synthetic resin is then poured into the exit end of the eye in an amount sufficient to fill the transverse spaces and any fissures in the handle and to extend across the extreme end of the handle, a depth of about :V16 to 1/8 inch being desirable for a good seal. To facilitate peneftration and flow into the spaces and fissures, the resin is preferably preheated to a temperature of 1Z0-150 F. and this preheating will also serve to facilitate curing thereof. Since the handle and eye are in firm, direct surface contact about their periphery adjacent the entrance end of the eye, the resin will not flow out the bottom of the eye and similarly, it will not enter between the handle and surface of the eye in the direction of percussive and leverage strains or forces except possibly for insignificant areas where surface imperfections may provide some small amount of spacing.

The tools are maintained in the upright position un-til the resin has set and may thereafter be placed in other positions for further curing. If so desired, the process of curing may be accelerated by heating the assembly.

As a specific example of the efficacy of the present invention, a number of 16ounce metallic head claw hammers were produced in accordance with the present invention and compared with 16ounce hammers conventionally produced using a wood wedge diagonally of the eye and a pair of steel wedges transversely thereof. Both 6 groups of hammersI employed conventional wood handles and tapered eyes such as illustrated in FIGS. 1-3 of the accompanying drawings.

In fabricating the hammers embodying the present invention, the heads were cleaned in accordance with conventional practical and dry, oil-free wood handles were driven thereinto. A single wood wedge equal to the width of the handle end was then driven into the end of the handle to expand the wood into firm engagement with the surface of the eye in the direction of percussive forces. The hammer head was preheated to about 150 F. and

the hammers were placed upright in racks.

A synthetic resin adhesive mixture containing three parts bis-phenol-A-epichlorohydrin and two parts Itertiary amine catalyst was preheated to about F. and then poured into exit ends of the eyes of the hammers to fill the spaces and provide a seal across the end of the handle and wedge. The hammers were maintained upright at room temperature for six hours to allow the resin to set and then stacked and allowed to cure for an additional twenty-four hours.

When subjected to impact testing by repeated striking of the poll and bell against a steel anvil, the resin-bonded hammers showed no change or looseness after 10,000 and 20,000 cycles, respectively; whereas, the conventionally produced hammers failed at 2594 cycles and 3300 cycles, respectively.

When subjected to a wiggle test wherein the head is maintained in a rigid position and the free end of the handle is moved back and forth by machine in a direction parallel to direction of percussion forces, the resin-bonded hammers showed no change after 30,000 cycles; whereas, one of the conventional hammers pulled apart after 1200 cycles and the wood in the eye of the other split after 1800 cycles.

These comparative tests clearly illustrate the superior properties of hand tools produced in accordance with the present invention.

As will be readily apparent to persons skilled in the art, various modifications and adaptations may be effected without departing from the spirit and scope of the invention.

I claim:

1. A hand tool for percussive use comprising a striking element having an aperture extending therethrough normal to the direction of percussive forces with entrance and exit ends; a handle having one end extending into the entrance end of said aperture and terminating adjacent to but inwardly of the exit end of the aperture; a wedge in said one end of said handle forcing the material thereof into direct surface contact with the striking element substantially throughout the entire depth of the aperture in the direction of percussive and leverage strains or forces, said handle and aperture being configured to provide close-fitting surface Contact throughout the periphery thereof adjacent the entrance end of the aperture and to provide minor spacing between the side surfaces of the handle and the surface of the aperture of the striking element adjacent the exit end thereof and transversely of the direction of percussive force; and an impact-resistant, synthetic resin adhesive in the spaces between the side surfaces of said handle and aperture lof the striking element and extending across the extreme end of the handle and wedge in the exit end of the aperture to seal the end of the handle and firmly bond said handle and wedge in position.

2. A hand tool in accordance with claim 1 wherein the `handle is non-metallic.

3. A hand tool in accordance with claim 2 wherein said striking element is a metal claw hammer head having a poll and striking face at' `one end and a pair of claws at the other end.

4. A hand tool in accordance with claim 1 wherein said resin is an epoxy.

5. A hand tool in accordance with claim 1 wherein said resin is a urethane.

6. A hand tool for percussive, prying or leverage use comprising a metallic striking head having an aperture extending therethrough approximately normal to the direction of the longitudinal axis of the head with entrance and exit ends, said aperture having a portion tapering inwardly from the entrance end and thence tapering outwardly to a larger cross section at said exit end; a non-metallic handle having one end extending into the entrance end of said aperture and terminating slightly inwardly of the exit end of the aperture; a wedge in said one end ofv said handle extending transversely of the direction of the longitudinal axis of the head and` forcing the material thereof longitudinally into direct surface Contact with the interior surface of the aperture substantially throughout the entire depth of the aperture in the direction of percussive, prying or leverage forces, said handle and aperture being configured to provide close-fitting surface contact throughout the periphery thereof from the entrance end of the aperture and for a portion of the distance therethrough, the side surfaces of said handle transversely of the direction of percussive force being spaced slightly from the surface of said aperture at the outwardly tapering portion thereof; and an impact-resistant, Synthetic resin adhesive in the spaces between the side surfaces of said handle and aperture of the striking element and extendingv across the extreme end of the handle in the exit end of the aperture across the end of the .handle and wedge to seal the end of the handle and wed ge and firmly bond said handle and wedge in position.

7. A hand tool for percussive, prying or leverage use comprising a metallic striking element having an aperture extending therethrough approximately normal to the direction of percussive force with entrance and exit ends; anon-metallic handle having one end extending into the entrance end of said aperture and terminating slightly inwardly of the exit end of the aperture; a wedge in said one end of said handle forcing the material thereof into direct surface contact with the striking element substantially/throughout the entire depth of the aperture in the .direction of percussive, prying or leverage forces, said lhandle having a portion of reduced cross section transversely of the direction of percussive force extending inwardly from its end adjacent said exit end of the aperture and terminating upwardly of the entrance end of the aperture to provide slight spaces between the side lsurfaces thereof and the surfaces of the aperture extend- .ing inwardly from the exit end of the aperture, said handle :and aperture being configured to provide close-fitting surface contact throughout the periphery thereof adjacent the entrance end of the aperture and for a portion of the distance therethrough; and an impact-resistant, synthetic plastic adhesive in said spaces between the side surfaces of said handle and aperture of the striking element and extending across the extreme end of the handle and wedge in the exit end of the aperture to seal the end of the handle and wedge and irrnly bond said handle and wedge in position.

References Cited by the Examiner UNITED STATES PATENTS 2,090,164 S/37 Vaughan 145-29 2,340,619 2/44 Schwarzmayr 145-29 2,571,350 10/51 Estwing 76-103 2,850,331 9/58 Curry et al 145-29 X 2,874,738 2/59 Lay 145-29 2,884,816 5/59 Lay 76-103 2,917,349 12/59 Saylor et al 145-29 X vVLLlAM FELDMAN, Primary Examiner.

MLTON S. MEHR, Examiner. 

1. A HAND TOOL FOR PERCUSSIVE USE COMPRISING A STRIKING ELEMENT HAVING AN APERTURE EXTENDING THERETHROUGH NORMAL TO THE DIRECTION OF PERCUSSIVE FORCES WITH ENTRANCE AND EXIT ENDS; A HANDLE HAVING ONE END EXTENDING INTO THE ENTRANCE END OF SAID APERTURE AND TERMINATING ADJACENT TO BUT INWARDLY OF THE EXIT END OF THE APERTURE; A WEDGE IN SAID ONE END OF SAID HANDLE FORCING THE MATERIAL THEREOF INTO DIRECT SURFACE CONTACT WITH THE STRIKING ELEMENT SUBSTANTIALLY THROUGHOUT THE ENTIRE DEPTH OF THE APERTURE IN THE DIRECTION OF PERCUSSIVE AND LEVERAGE STRAINS OR FORCES, SAID HANDLE AND APERTURE BEING CONFIGURED TO PROVIDE CLOSE-FITTING SURFACE CONTACT THROUGHOUT THE PERIPHERY THEREOF ADJACENT THE ENTRANCE END OF THE APERTURE AND TO PROVIDE MINOR SPACING BETWEEN THE SIDE SURFACES OF THE HANDLE AND THE SURFACE OF THE APERTURE OF THE STRIKING ELEMENT ADJACENT THE EXIT END THEREOF AND TRANSVERSELY OF THE DIRECTION OF PERCUSSIVE FORCE; AND AN IMPACT-RESISTANT, SYNTHETIC RESIN ADHESIVE IN THE SPACES BETWEEN THE SIDE SURFACES OF SAID HANDLE AND APERTURE OF THE STRIKING ELEMENT AND EXTENDING ACROSS THE EXTREME END OF THE HANDLE AND WEDGE IN THE EXIT END OF THE APERTURE TO SEAL THE END OF THE HANDLE AND FIRMLY BOND SAID HANDLE AND WEDGE IN POSITION. 